Post-Brexit trade, security and overseas aid have featured in her three-day Africa visit as she made the case for the UK to seize a greater share in the market amid fierce global competition from China, France and the United States.

On the Kenyan security pact, Mrs May said: “Online child exploitation is an abhorrent crime and we are determined to ensure there is no place to hide for predators who use the internet to share images of abuse across borders, too often with impunity.

“This builds on our ongoing work with Kenya on security and criminal justice – a partnership which has already helped to convict and imprison terrorists in the UK.”

The cyber centre project is linked to Kenya’s existing anti-human trafficking and child protection unit, which involves the UK’s National Crime Agency.

This unit has helped protect around 499 children since March 2016 and helped secure convictions of British paedophiles who have sexually abused children in Kenya, Downing Street said.